This invention relates to the nuclear-reactor art. It has particular relationship to the repair of the damaged, cracked or corroded tubes, of a steam generator of a nuclear-reactor plant. In accordance with the teachings of Cooper and other related teaching, the repair of the damaged tubes is effected by inserting sleeves in the tubes and providing metallically sealed joints between the sleeves and the sleeved tubes. To carry out this operation, an operator must enter the channel head of the generator and set the sleeves for a sleeving operation. The environment within the channel head is radioactive. Extensive studies have shown that the task which the operator must perform during sleeving insertion renders this process the most radiation-exposure-intensive operation within the overall sleeving process. In accordance with the teachings of Cooper, the sleeve blanks are inserted in the tubes one at a time. While the Cooper invention has performed highly satisfactorily, its ability to carry out only one sleeve insertion operation at a time constitutes a disadvantage. For each sleeving operation, an operator must expose himself to radioactivity by entering the channel head to position a sleeve blank and the mandrel on Cooper's sleeve inserter and otherwise to adjust or to set the sleeve inserter.
In Cooper, an expander is required to expand the inserted sleeves so that they are held in the tubes until they can be metallically sealed. The demand for an expander accentuates the requirement that the tubes be sleeved one at a time which in turn entails the repeated exposure to radioactivity of operators.
It is an object of this invention to minimize the exposure of personnel to radioactivity on the sleeving of damaged, cracked or corroded tubes of a steam generator of a nuclear-reactor plant and to provide a method for accomplishing this purpose which shall not require the expansion of the sleeves in the tubes.